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How worried should you be about coronavirus variants? A virologist explains his concern
A COVID-19 patient in an ICU unit in a hospital in Capetown, South Africa, in December 2020. A variant originated in South Africa that has since spread to other parts of the world. Other new variants may appear elsewhere. Rodger Bosch / AFP via Getty Images Spring has arrived, and there is a sense of relief in the air. After one year of obstruction and social distance, more than 171 million doses of COVID-19 vaccinations have been administered in the US and approximately 19.4% of the population have been fully vaccinated. But there’s something else up in the air: ominous SARS-CoV-2 variants. I am a virologist and vaccinator, which means I spend my days studying viruses and designing and testing vaccination strategies against viral diseases. In the case of SARS-CoV-2, this work has become increasingly urgent. Our humans are in a race to become immune to this scavenger virus, whose ability to mutate and adapt appears to be a step ahead of our ability to gain herd immunity. Due to the variants that pop up, it can be a race to the wire. A variant in Brazil is overwhelming in the country’s healthcare system. Five variants to watch as RNA viruses like SARS-CoV-2 constantly mutate as they make more copies of themselves. Most of these mutations are ultimately detrimental to the virus and thus disappear by natural selection. Sometimes, however, they offer an advantage to the mutated or so-called genetic variant virus. An example is a mutation that improves the ability of the virus to attach more strongly to human cells, thus enhancing viral replication. Another is a mutation that allows the virus to spread more easily from person to person, thus increasing transmissibility. None of this is surprising for a virus that is a new arrival in the human population and is still adapting to humans as hosts. Although viruses do not think, they are driven by the same evolutionary driving force that all organisms are – their first business area is to sustain themselves. These mutations led to several new SARS-CoV-2 variants that led to outbreak groups, and in some cases, worldwide spread. They are broadly classified as variants of interest, concern or major consequences. Currently, five varieties of concern are spreading in the US: the B.1.1.7, which originated in the United Kingdom; the B.1.351., of South African origin; the P.1., first seen in Brazil; and the B.1.427 and B.1.429, both in California. Each of these variants has a number of mutations, some of which are key mutations in critical regions of the viral genome. Because the vein protein is needed to attach the virus to human cells, it carries a number of these key mutations. In addition, antibodies that neutralize the virus typically bind to the vein protein, making the vein sequence or proteins an important component of COVID-19 vaccines. India and California have recently detected ‘double mutant’ variants which, although not yet classified, have gained international interest. They have one key mutation in the ear protein similar to one found in the Brazilian and South African variants, and another already found in the B.1.427 and B.1.429 variants in California. As of today, no variant has been classified as of major importance, although the concern is that it may change as new variants emerge and we learn more about the variants already in circulation. More transmission and worse disease These variants are worrying for several reasons. First, the SARS-CoV-2 variant usually spreads from person to person at least 20% to 50% more easily. This enables them to infect more people and spread faster and wider and eventually become the dominant tribe. For example, the B.1.1.7 UK variant first detected in the US in December 2020 is now the prevailing strain in the US, accounting for approximately 27.2% of all cases by mid-March. Similarly, the P.1 variant, first detected in Brazilian travelers in January, is now devastating in Brazil, where it caused a collapse of the health care system and led to at least 60,000 deaths in March. Second, SARS-CoV-2 variants that are of concern may also lead to worse diseases and increased hospitalizations and deaths. In other words, they may have improved virulation. Indeed, a recent study in England suggests that the B.1.1.7 variant causes serious illnesses and deaths. Another concern is that these new variants may escape the immunity caused by natural infection or our current vaccination efforts. For example, antibodies from people who recover from infection or who have received a vaccine may not bind as effectively to a new variant virus, leading to reduced neutralization of the variant virus. This can lead to reinfections and reduce the effectiveness of current monoclonal antibody treatments and vaccines. Researchers are intensively investigating whether there is a reduced vaccine efficacy against these variants. While most vaccines appear to remain effective against the British variant, a recent study showed that the AstraZeneca vaccine is not effective in preventing COVID-19 from moderate to moderate due to the South African variant B.1.351. On the other hand, Pfizer recently released data from a subset of volunteers in South Africa that support the efficacy of its mRNA vaccine against the B.1.351 variant. Other encouraging news is that T-cell immune responses are caused by natural SARS-CoV-2 infection or mRNA vaccination, all three of the British varieties, South Africa and Brazil recognize. This suggests that T cell responses stimulated by vaccination or natural infection, even with reduced neutralizing antibody activity, will provide some protection against such variants. Stay awake and get vaccinated What does it all mean? Although current vaccines may not prevent mild symptomatic COVID-19 by these variants, they are likely to prevent moderate to severe illness, and in particular hospitalizations and deaths. That is the good news. However, it is essential to assume that the current SARS-CoV-2 variants are likely to continue to evolve and adapt. In a recent survey among 77 epidemiologists from 28 countries, the majority believed that current vaccines should be updated within a year to better handle new variants, and that the low vaccine coverage is likely to facilitate the emergence of such variants. What should we do? We must continue to do what we have done: use masks, avoid poorly ventilated areas and use social distance techniques to delay transmission and prevent further waves driven by these new variants. We also need to vaccinate as many people in as many places and reduce the number of cases as soon as possible and the likelihood that the virus will generate new variants and mutants can escape. And for that, it is essential that public health officials, governments and non-governmental organizations address the hesitation and fairness of vaccines locally and globally. [Insight, in your inbox each day. You can get it with The Conversation’s email newsletter.]This article was published from The Conversation, a non-profit news site dedicated to sharing ideas from academic experts. It was written by: Paulo Verardi, University of Connecticut. Read more: New COVID variants have changed the game and vaccines will not be enough. We Need Global ‘Maximum Suppression’ What you need to know about the new COVID-19 variants, Paulo Verardi receives funding from NIH, USDA, DOD and the University of Connecticut.